Starting with the =x11-base/xorg-server-1.11 package, the X.Org X Server
again provides debugging functionality that can be used terminate an
application that exclusively grabs mouse and keyboard input, like screen
locking utilities.
Gu1 reported that the X Keyboard Configuration Database maps this
functionality by default to the Ctrl+Alt+Numpad * key combination.

Impact

A physically proximate attacker could exploit this vulnerability to gain
access to a locked X session without providing the correct credentials.

Workaround

Downgrade to any version of x11-base/xorg-server below
x11-base/xorg-server-1.11:

NOTE: The X.Org X Server 1.11 was only stable on the AMD64, ARM, HPPA,
and x86 architectures. Users of the stable branches of all other
architectures are not affected and will be directly provided with a fixed
X Keyboard Configuration Database version.